Extraction of Entities and Relations调研
Extraction of Entities and Relations调研，后面将推出基于Stanford Parser 的具体实现
Phrase Dependency Parsing? A lot of product features are phrases? Phrase dependency parsing extends traditional dependency parsing tophrase level? Relation extraction task can benefit from dependencies within a phrase.
The Approach? (1) Constructing phrase dependency tree from results of chunking and dependency parsing;? (2)Extracting candidate product features and candidate opinion expressions;? (3) Extracting relations between product features and opinion expressions.Phrase Dependency Tree ? Toolkit: Stanford parser,MXPOSTCandidate Product Features and Opinion Expressions? Product Features All NPs and VPs are selected as candidate product features. Prepositional phrases (PPs) and adjectival phrases (ADJPs) are excluded.? Opinion Expressions Use a dictionary which contains 8221opinion expressions to select candidates. The tree distance between product featureand opinion expression in a relation should be less than 5.RelationExtraction? Taking advantage of the kernel methods? Instances containing similar relationswill share similar substructures in their dependency trees? Generalize the definition by (Culotta andSorensen, 2004) to fit the phrase dependency tree.Tree kernels fordependency trees? List of features assigned to nodes Tree kernels for dependency trees? Matching function and similarity function
Kernel function for PDT? Add term Kin to handle theinternal nodes of a phrase
Relation Extraction Experiment? Corpus and features? Restricting nodes by m(ti, tj) is a way toprune the search space of matching subtrees
Relation Extraction Experiment
ILP and SRL Approach
Extract Entity and Opinion on the Forum and Twitter? Description of task:Who feels how on which aspects of which entity?? Sentiment towards involved entities? Sentiment towards participants? Extracting sentiment expressions from Twitter Reference? Yejin Choi, Eric Breck, and Claire Cardie.2006. Joint extraction of entities and relations for opinion recognition. InProceedings of EMNLP.? Aron Culotta and Jeffrey Sorensen. 2004.Dependency tree kernels for relation extraction. In Proceedings of ACL 2004.? Yuanbin Wu, et al. 2009. Phrase Dependency Parsing for Opinion Mining.In Proceedings of EMNLP.